Conventionally, electrical circuits, such as electrical connection boxes and fusible links, for use in automotive electrical equipment have been provided with a terminal mounting portion on which conduction members, such as bus bars, that constitute part of the electrical circuit are mounted. Such a conventional electrical circuit employs a terminal connection structure in which the electric circuit is brought into conduction with an electrical wire by fastening to the terminal mounting portion a bolt tightening terminal provided at an end of an electrical wire with a bolt. For example, JP 2001-231131A discloses a structure in which a stud bolt is erected in advance on the terminal mounting portion on which a bus bar is provided. According to this structure, the stud bolt is passed through the bolt insertion hole in the bolt tightening terminal at one end of an electrical wire, the bolt tightening terminal is then mounted on the terminal mounting portion with the bolt tightening terminal engaging the stud bolt, and subsequently a nut is tightened on the stud bolt.
In recent years, due to the increasing number of electrical components mounted on vehicles and demands for downsizing vehicles, the onboard space for electrical circuitry is increasingly limited. Accordingly, it is sometimes difficult to dispose a stud bolt with a large projection as in JP 2001-231131A. To address such a situation, for example, JP 2011-223693A discloses a structure in which a nut is disposed in advance in the terminal mounting portion. According to this structure, a bolt tightening terminal is mounted on the terminal mounting portion with the bolt insertion hole of the bolt tightening terminal aligned with the threaded hole of the nut, and a connecting bolt, generally smaller than a stud bolt, is passed through the bolt insertion hole and then tightened to the threaded hole of the nut.
In the terminal connection structure disclosed in JP 2011-223693A, before the connecting bolt is tightened to the nut, the bolt tightening terminal of the electrical wire terminal is simply set on the terminal mounting portion without being secured. According to this structure, therefore, the bolt tightening terminal is more likely to fall off the terminal mounting portion compared with the bolt tightening terminal of the terminal connection structure disclosed in JP 2001-231131A in which a stud bolt is engaged with a bolt tightening terminal. Additionally, this structure has the inherent problem that the bolt tightening terminal is easily displaced from the proper mounting position in which the bolt insertion hole of the bolt tightening terminal and the threaded hole of the nut are aligned with each other. This may adversely affect the efficiency with which the bolt tightening terminal is fastened to the terminal mounting portion.
One conceivable solution might be to employ a structure in which the bolt tightening terminal is fitted into the terminal mounting portion before the bolt tightening terminal is fastened with a connecting bolt as this can maintain the alignment between the bolt tightening terminal and the terminal mounting portion. However, this would require a large force to mount the bolt tightening terminal in the terminal mounting portion, again possibly affecting the work efficiency.
JP 2001-231131A and JP 2011-223693A are examples of related art.